JP6966737B2 - Small removable microscope-mounted keratometer for cataract surgery - Google Patents

Description

This application claims priority to US Provisional Application No. 62 / 391,343 filed on April 28, 2016, which provisional application is in every effort as described herein. Incorporated by reference for purposes.
The present invention relates to a diagnostic device and a method of applying the diagnostic device, in particular to a removable keratometer for intraoperative measurement mounted under a surgical microscope and a method of using the keratometer.

Cataract surgery is the most common surgery in the world. Currently, 3 million cataract surgeries are performed annually in the United States. There are also 3 million cataract surgeries performed in Western Europe. WHO estimates that by 2020, there will be 32 million cataract surgeries, more than 12 million in 2000. This is not simply due to longer lifespans and an increase in the baby boomer's statistical population. More people are using digital devices (tablets, smartphones) and continue to live an active life after retirement. Therefore, more people are choosing to perform cataract surgery and gain a functional view.

Cataract surgery is a process of extracting a cataract (opaque) crystalline lens from a patient's eye and replacing the crystalline lens with an artificial intraocular lens (IOL). To prescribe intraocular lens implants, many ocular measurements (biomeasures) are currently performed prior to surgery to obtain the best visual function results. Critical parameters such as axial length, corneal radius, and anterior chamber depth are measured. Currently, due to inadequate accuracy of biometrics, cataract surgery results are poor at a rate of 50%, in which case the patient has a surgical result of> 0.5 diopter refraction error and wears eyeglasses after surgery. Must be worn. The lack of instruments for measuring astigmatism during surgery has stagnated the adoption of toric IOLs to correct astigmatism.

When light is reflected from the human eye, the anterior corneal (first Purkinje image), posterior corneal (second Purkinje image), and anterior crystalline lens (third Purkinje image), known as the first to fourth Purkinje images. ), And there are four reflections from the posterior surface of the lens (fourth Purkinje image). The measurement of corneal radius of curvature (Ks) was previously described by Placido in 1880 in the paper "a novo instrumiento par analyze immediate das irregularidades de curvature de cornea," Periodico Ophthalmol Practica 1880: 6: 44-49. It is based on the Pratide corneal curvature measurement technique. The placidling reflex (first Purkinje image) from the anterior surface of the cornea is analyzed to extract corneal curvature information.

U.S. Pat. No. 4,046,463 (Patent Document 1) provides the design of a platidling-based keratometer mounted under a surgical microscope. The shape of the ring is measured via a visual comparison with the reticle. The keratometer is a corneal anterior profile by measuring the parameters of a plaid ring elliptical first Pulkinje image formed by a ring-shaped light source located below the microscope objective and above the patient's eye. Allows you to measure spheres, cylinders, and angles.

U.S. Pat. No. 4,597,648 (Patent Document 2) describes a compact microscope-mounted keratometer that uses a linear video sensor with scanning optics to capture an image of placid ring reflected from the cornea. There is. The ring image is generated by a circular light source (optical fiber and LED) mounted on the bottom side of the keratometer. The image is digitized and processed by a computer processor. The surgeon is informed during surgery about the astigmatic axis angle via a live video image of the eye on a video monitor by digitally superimposed lines that specify the astigmatic angle. In addition, the two LEDs closest to the astigmatic angle on the keratometering are brightened by the processor, creating two bright spots on the patient's cornea, indicating the astigmatic angle. U.S. Pat. No. 5,307,096 (Patent Document 3) recommends that a computer that analyzes the first Purkinje image of the platidling display an image representing the shape of the cornea. U.S. Pat. No. 5,349,398 (Patent Document 4) recommends that such an image be a topographic map displayed on the eye in parallel with surgery. US Pat. No. 5,349,398 contains many different forms of intraoperative information display, such as (1) video display of corneal limbus, (2) numerical display of spherical curvature, astigmatism, asphericity, etc., and / Or (3) recommend recommended surgical steps to correct for observed errors in corneal shape. U.S. Pat. No. 5,349,398 also recommends that the surgeon adjust the sutures to correct the aspherical nature of the cornea.

U.S. Pat. No. 4,660,946 (Patent Document 5) describes a similar system for tabletop keratometers for patient visits. U.S. Pat. No. 4,660,946 is based on CCD video registration and acquires a plaid ring image within a single frame. The computer is then used to process a digital image of the corneal radius.

One of the difficulties is applying preoperative bioassays, which are usually performed two weeks before surgery, to intraoperative guidance. This is especially true when transferring the orientation of the astigmatic angle for toric IOL alignment. Many methods have been developed using video and image enrollment to transfer the astigmatic angle measured at the time of visit to the intraoperative guidance. This is because the eye rotation causes the patient's eye on the operating table to rotate with respect to the visual axis from the direction of the eye in the patient sitting at the time of visit. One method is to take an image of the patient's intubal blood vessels at the time of visit and later use the image as a marker for enrolling an image of the patient's eye during surgery (eg, US Pat. No. 7). , 905, 887 (Patent Document 6) and US Pat. No. 8,414,123 (Patent Document 7)). The additional image registration step here adds an error to the original preoperative astigmatism angle measurement. In addition, surgery-induced astigmatism (SIA) that occurs after measurement due to corneal incision during surgery cannot be accurately compensated. A better method is to make on-site refractive measurements during surgery to avoid the need for pre- and intra-surgery eye image registration with registration errors and to adequately compensate for SIA (eg, USA). See Patent No. 7,988,291 (Patent Document 8) and US Pat. No. 8,882,270 (Patent Document 9)). These are very complex and expensive optics that are large in size and occupy up to 30% of the surgical space under the microscope during cataract microsurgery.

U.S. Pat. No. 4,046,463 U.S. Pat. No. 4,597,648 U.S. Pat. No. 5,307,096 U.S. Pat. No. 5,349,398 U.S. Pat. No. 4,660,946 U.S. Pat. No. 7,905,887 U.S. Pat. No. 8,414,123 U.S. Pat. No. 7,988,291 U.S. Pat. No. 8,882,270

Despite numerous keratometer designs in the past, all of these keratometers are in-hospital devices where the patient and doctor sit at the table, face each other, and place a tabletop keratometer between them. Several microscope-mounted keratometers have been proposed, but none of them have been realized in commercial products. This is because it is difficult to obtain high accuracy with a small microscope-mounted device, that is, a device whose size is limited by the available surgical space. Therefore, there is a need for a small, removable microscope-mounted keratometer for live surgical corneal curvature measurement.

In one embodiment, the invention provides an intraoperative measurement keratometer mounted under a surgical microscope. The keratometer includes a placid ring that illuminates the patient's eye, a video camera, a beam splitter that directs the Purkinje image of the placid ring to the video camera, and patient eye fixation, fixation confirmation, or IOL imaging and cataract vision. A fixed vision lamp that directs a beam to produce a red reflection effect to emphasize the formation of the IOL, and an IOL form to identify the refraction characteristics and keratometer parameters of the patient's eye and to assist in IOL alignment. It includes a processor configured to perform a digital image enhancement method for contouring and a digital display displaying said keratometer parameters and surgical guidance information for the surgeon.

In another embodiment, the placid ring is configured to flash at the frame per second rate of the video camera and skip flash for at least one frame for background recording and background subtraction.

In another embodiment 0.02% to 30% of the Purkinje image is defined as a small region of interest window and is used to extract information from the Purkinje image for high frame per second measurement and averaging. NS.

In another embodiment, the keratometer further comprises an fixation detector. The fixation lamp is a substantially collimated visible or NIR light source of integral fixation pulsating at a frequency of 0.5 Hz to 1 MHz, and the fixation detector confirms that the patient has followed. Accept accurate fixation measurements.

In another embodiment, the keratometer further comprises an integrated optical coherence tomography scanner. The integrated optical coherence tomography scanner extracts information about the surface curvature, anterior chamber depth, and IOL placement of the posterior surface of the cornea.

In another embodiment, the digital display is incorporated into the keratometer as a digital overlay display.

In another embodiment, the substantially collimated visible or NIR light source produces a fundus reflex effect due to video contrast when always operating in "on" mode.

In another embodiment, the digital image enhancement method is applied to live video to outline an IOL feature to facilitate IOL alignment.

In another embodiment, the different optical channels of the placid ring, the fixation lamp, the fixation detector, and the Purkinje image are spectrally separated for coaxial operation.

In another embodiment, an angular offset in degrees is applied to ensure the difference between anterior corneal astigmatism and total corneal astigmatism, and the combination of anterior corneal astigmatism and posterior corneal astigmatism is applied to the GUI. ..

In another embodiment, the present invention provides a method for measuring corneal curvature. The method involves receiving a Purkinje image and background image of the patient's eye from a keratometer video camera mounted under a surgical microscope with proper control of the placid ring and fixation lamp, and by a processor. Steps to perform analysis software to identify refraction characteristics and keratometer parameters of the patient's eye based on the Pulkinje and background images, and digital image enhancement methods to outline the IOL to aid in IOL alignment. And include displaying a live line indicating the specified astigmatic angle of the eye on the image of the patient's eye.

In another embodiment, the placid ring flashes at the frame per second rate of the video camera, skipping flash for at least one frame for background recording and background subtraction.

In another embodiment, different optical channels are spectrally separated for coaxial operation.

In another embodiment, the corneal curvature measuring method is a collimated visible or NIR light source of integral fixation pulsating at a frequency of 0.5 Hz to 1 MHz and a solid to confirm that the patient has followed. It further includes a step of providing a visual detector and a step of accepting an accurate fixation measurement.

In another embodiment, the method for measuring corneal curvature is the first, second, third, and fourth tomographic images and / to extract information about the surface curvature, anterior chamber depth, and IOL placement of the posterior surface of the cornea. Or further include the step of using an integrated optical coherence tomography scanner.

In another embodiment, the corneal curvature measuring method further comprises the step of using a precision diameter sphere of known size for calibration.

In another embodiment, the analysis software is configured to calculate the astigmatism angle by offset to compensate for the preoperative total corneal astigmatism angle delta.

In another embodiment, the method of measuring corneal curvature enhances IOL contrast or assists in cataract visualization with a step of providing a substantially collimated visible or NIR light source for fixation in the patient's eye. Further includes steps that produce a red reflection effect.

In another embodiment, the refraction property and the commentary line are integrated with a tablet PC, an external display mountable on the surgical microscope, or the keratometer that brings a digital overlay into the surgeon's surgical view. Shown on the digital display.

In another embodiment, the analysis software applies a fast Fourier transform to analyze the Pulkinje image for elliptic parameter extraction.

In another embodiment, the corneal curvature measuring method further comprises applying 0.02% to 30% of the Purkinje image captured by the video camera for high frame per second measurement and averaging.

In another embodiment, the corneal curvature measuring method includes a preoperative biometric step, a keratometer calibration step, a surgical removal step of the cataract lens, an eye pretreatment step for intraoperative corneal curvature measurement, and a microscope. Further centering step, microscope height adjustment step, LED brightness adjustment step, patient fixation step, corneal curvature measurement step, cataract line display step, toric IOL implantation and alignment step. include.

It should be understood that both the above schematic description and the detailed description below are exemplary and descriptive and are intended to provide further description of the invention as claimed. be.

The accompanying drawings are included to bring about a further understanding of the invention, which is incorporated herein by reference and constitutes a portion of the specification, but illustrates embodiments of the invention and described above. At the same time, it is useful for explaining the principle of the present invention.
The drawings are as follows.

It is a figure which depicts one removable keratometer which concerns on one Embodiment of this invention. 101 is a surgical microscope, 102 is a removable keratometer, 103 is a surgical eye, 104 is a platidling light source, 105, 106 and 108 are beam splitters, 107 is a fixation lamp, 109 is a fixation detector, 110 is an objective lens. A keratometer video camera comprising, 111 is an optical filter, 112 is a digital display with a lens. It is the figure which showed the spectral separation of the optical channel of a removable keratometer. λ1 = 420nm to 650nm, λ2 = 560nm, λ3 = 750nm, λ4 = 875nm, and λ5 = 660nm, 201 is the patient's eye, 202 to 204 are the optical beam splitter, 205 is the optical filter, 206 is the video camera, 207 is the lens. It is a digital display equipped with. On the right, the schematic reflection spectra of optics 202-205 are depicted for the current implementation. The anti-phase operation of the platidling (according to signal 31) and the fixation lamp (according to signal 32) for "NIR red reflection" illumination allows both λ3 and λ4 to pass through to the video camera. It is a figure. As a result, when the placid ring is off at stage 34, the NIR beam remains on at stage 33 and can be used for "NIR red reflection" imaging of IOLs and cataracts by video cameras. FIG. 6 depicts a calibration tool for several diameter metal spheres (41-44) to be calibrated held at the same vertex height level so that the microscope does not need to be refocused during calibration. Achieve preoperative biomeasurement step S1, keratometer calibration step S2, cataract removal step S3, eye pretreatment step S4, microscope centering step S5, microscope height adjustment step S6, LED brightness adjustment step S7, patient fixation. It is a figure which showed the corneal curvature measurement method and process flow during surgery as a block diagram in step S8, measurement step S9, step S10 which displays an ectopic line of sight, toric IOL alignment step S11, and step S12 which ends cataract surgery. It is a figure which described the concept of CMOS window generation for increasing the speed of a platidling image acquisition frame per second. It is a figure which showed the fixation | fixation detector based on the red fundus reflex which concerns on one Embodiment of this invention. It is a figure explaining the pulse light platidling corneal curvature measurement for background subtraction. It is a figure explaining the Fourier analysis method applied to identify the parameter of the first Purkinje image of an ellipse. It is a figure which described the calibration GUI. It is a figure which described the measurement GUI. It is a figure which depicts one removable keratometer which concerns on another embodiment of this invention. 101 is a surgical microscope, 102 is a removable keratometer, 103 is a surgical eye, 104 is a platidling light source, 105 is a beam splitter, 110 is a keratometer video camera with an objective lens, 112 is a digital display with a lens, 1200 is. A processing unit, 1201 is an OCT laser and an optical system, 1202 is an OCT scanner, 1203 is a beam splitter, 1204 is an optical fiber, and 1205 is a microscope-mounted video monitor.

It will be apparent to those skilled in the art that various modifications and modifications can be made in the invention without departing from the spirit or scope of the invention. Accordingly, if the modifications and modifications of the present invention are within the scope of the appended claims and their equivalents, the present invention is intended to include those modifications and modifications.

Hereinafter, embodiments of the present invention will be referred to in detail, but examples of embodiments of the present invention are shown in the accompanying drawings.

FIG. 1 schematically illustrates one proposed implementation of the recommended small removable keratometer device. The surgical microscope 101 has a keratometer device 102 attached to the bottom of the surgical microscope 101, that is, above the patient's eye 103. In the keratometer device 102, one illuminated platid ring 104 (or a plurality of platid rings) is attached to the bottom of the keratometer device 102. FIG. 1 shows twelve separate light sources, the Platid Ring 104, as a ring formed by an LED. However, one of ordinary skill in the art recognizes that other means of platiding, i.e., continuous illuminated rings based on fiber optics or dispersed optical materials, are available. The number of separate light sources can be changed. One or more plaid rings can be projected by using a projection lens and an OLED display or reticle illuminated by a light source. Next, the first Purkinje image of the placid ring 104 formed on the anterior surface of the cornea of the patient's eye 103 is reflected to the video camera 110 by the beam splitter 105. The video camera 110 has a built-in objective lens and has an optical filter 111 in front of the objective lens in order to reduce the background light. The beam splitter 106 is used to reflect light from a blinking fixation lamp 107, that is, an LED or the like. The beam splitter 108 is used to combine the image of the patient's eye 103 into the fixation detector 109, i.e., a device that confirms that the patient has complied with the fixation request, i.e., so-called fixation confirmation. NS. The digital display 112 is designed to bring digital graphics into the surgical field of view of the surgeon in the surgical field through the lens system. The digital display 112 can be based on OLEDs, LCDs, DLPs, LCOS, or other display and projection techniques. FIG. 1 shows how the keratometer device 102 is attached to the microscope 101, but the device can also be attached as a tabletop type. Desktop systems may be useful for systems placed in ophthalmology to plan surgery. The video information from the video camera 110 is then sent to a processor or tablet PC (not shown in FIG. 1) to identify the refraction characteristics and keratometer parameters of the patient's eye. The tablet PC or a separate display or monitor is attached to the surgical microscope 101 or other mounting table.

In FIG. 1, many optical components or devices operate coaxially. The visual path and illumination path of the surgical microscope 101 coincide with the optical path to the camera 110, the fixation lamp 107, and the fixation detector 109. It is clear that spectral differences can be used to achieve separation of different optical channels. FIG. 2 depicts the four separation elements of such an implementation: beam splitters 202, 203, 204 and optical filter 205. The patient's eye 201 is observed by the surgeon via the beam splitter 202 over the entire visible range of wavelengths _{here shown as λ 1.} The pulsating light of the fixation source _{can have any visible wavelength λ 2} , but is preferably red for high visibility. The light is pulsating so that it is easy to find and fix the light at the same time as the patient is illuminated by the light of the microscope. The characteristic pulsation rate should be somewhere between 0.5 Hz and 15 Hz, 1 Hz and 10 Hz, or 0.5 Hz and 1 MHz so that it can be perceived. The fixation lamp is reflected by the beam splitter 203 and the beam splitter 202. The beam splitter 202 is designed to pass through the entire (or almost all) visible range for proper microscopy function, but at a 45 degree angle, it has a residual reflectance coefficient _{for wavelength λ 2 of the fixation lamp.} It is enough. The beam splitter 204 is _{designed to reflect the fixation detection wavelength λ 3} and pass through the placid ring source wavelength λ _4. The optical filter 205 is _{designed to pass through λ 4} and block all other wavelengths to prevent background light interference. And finally, the beam splitter 202 can also be used to upwardly reflect the image of the digital display 112 at _{wavelength λ 5.} Such a digital display can be used to superimpose digital symbols and strings in the field of view of the surgeon in the surgical field. For example, a digital line can be projected to indicate the astigmatic angle. Various wavelength combinations can be used. Infrared radiation can be used for the platidling illumination so that the patient does not see the platidling. One of the proposed implementations has the following series of wavelengths: λ ₁ = 420 nm to 635 nm, λ ₂ = 560 nm, λ ₃ = 750 nm, λ ₄ = 850 nm, and λ ₅ = 635 nm. FIG. 2 also shows the schematic reflection spectra of the optical elements 202-205 depicted for the current implementation. For those of skill in the art, other spectral wavelengths can achieve similar spectral separation effects for keratometers. For example, the fixation lamp can be light in the visible range or light in the NIR range.

At the time of keratometer measurement, the placid ring 104 and the fixation lamp 107 can be turned on in the anti-phase mode as shown in FIG. Such a platidling image (Purkinje image) does not have an image of a bright spot from the fixation lamp 107. In addition, after the measurement is complete, the fixation light 107 remains lit to provide a strong on-axis NIR or visible beam for better IOL (intraocular lens) imaging or cataract during IOL alignment. It produces a "red reflection" effect on the keratometer video camera 110 for cataract visualization during removal surgery. The "red reflection" effect is obtained when the illumination of the light source is reflected by the patient's fundus, resulting in back illumination of the cataract lens or IOL for better visibility and higher contrast. Correspondingly, various digital image enhancement methods are applied to the live video of the keratometer video camera 110 to outline the features of the IOL for ease of IOL alignment. This is done by a processor or tablet PC. _{As shown in FIG. 3, both λ 3} and λ ₄ are passed to the video camera 110 due to the anti-phase operation of the plating 104 by the signal 31 for “NIR red reflection” illumination and the fixation lamp 107 by the signal 32. Can be done. As a result, in stage (33) of FIG. 3, when the LED ring is off (stage 34), the NIR beam can be used for "NIR red reflection" imaging of IOLs and cataracts by a video camera. The anti-phase operation of the pladidling and fixation lamp for "NIR red reflection" illumination temporarily separates the on-time of the plaid ring and fixation lamp, and the on-time of pure NIR light detects fixation. You will be able to support. The red reflected beam wavelength can also be _{far red λ 3} ≧ 530 nm to provide the surgeon with visible back illumination of the IOL when viewed through the microscope 101.

FIG. 4 shows an outline of a calibration device for the keratometer device. The calibration jig is equipped with several precision diameter metal spheres (41 to 44). The current implementation has four spheres with ranging diameters of 1000 inches, 0.875 inches, 0.750 inches, and 0.675 inches. The diameter of the sphere is selected to include a range of human corneal curvature. A stepped pedestal is adopted to make the vertices of each sphere the same height. The same height level is necessary to maintain a constant camera magnification without refocusing the microscope during calibration. The calibration mode of the keratometer continuously requests spheres of different sizes and records a platidling image of the spheres. This allows a calibration curve to be created and any diameter of the camera image of the plaid ring can be directly converted to the radius of curvature of the surface that produced the first Purkinje image of the plaid ring.

FIG. 5 depicts the method and flow of measuring corneal curvature during surgery as a block diagram. Successful corneal curvature measurement during surgery depends on the steady execution of these processing steps, resulting in accurate corneal curvature measurements.

S1 is a preoperative bioassay. This may be ultrasound or optical imaging. Typically, important eye biometric parameters required to prescribe an intraocular lens are axial length AL, corneal curvature Ks, astigmatism angle A, anterior chamber depth ACD, and the like.

S2 is the calibration of the microscope-mounted keratometer. This is done using the calibration tool depicted in FIG. 4 or an analog thereof. Precision diameter spheres of several diameters in the range of 0.5 inch to 1.0 inch are presented. The plated ring images of different precision diameter spheres are analyzed for the ring diameter and a calibration curve is generated.

S3 is cataract removal (ultrasonic lens emulsification suction or femtolaser). This involves all the usual cataract surgery steps, from incision to lens removal and lens capsule polishing.

S4 is an eye pretreatment. Prior to the corneal curvature measurement, the measurement can be made on the patient's eye and the intraocular pressure is reduced from about 20 mmHg to 30 mmHg. Preferably, this should be done using a contact tonometer. After lowering the IOP, moderate hydration closes the corneal incision. Excessive hydration can distort the corneal shape and Ks readout.

S5 is the centering of the microscope with the patient's eye. Rough centering can be performed by moving the microscope optical system laterally in XY coordinates. Fine alignment can be done by clicking on the square area of interest (ROI) of the corneal curvature measurement on the GUI touch screen of the keratometer and dragging the area of interest to center it with the first Purkinje image of the platidling. can.

In S6, the height of the microscope is adjusted at the maximum magnification. This is an important step as the measured values of corneal curvature measurements are directly affected by height. Since the depth of field (DOF) of the microscope is very shallow at maximum magnification, it is used for calibration and precise height positioning during corneal curvature measurements. The surgeon is requested to maximize the magnification and focus on the corneal apex to match the height of the calibrated sphere apex. This brings the height of the microscope and keratometer closer to the height used in the calibration.

S7 is a brightness adjustment of the plaid ring for the best image quality. This is done automatically by the software after the surgeon presses the "Measure" button. Manual options are also available.

S8 is to achieve patient fixation to a blinking fixation light. The patient is asked to see the flashing visible light on the top. The fixation detector confirms that the patient has followed and reads the corneal curvature measurement only at the moment the patient follows the fixation.

S9 is a measurement, i.e., acquisition of the first Pulkinje reflection image (typically 6 to 500) of the platidling. Next, the corneal radius and K value are calculated using the calibration curve obtained in the calibration step. Check if the error is less than the set limit, that is, typically the corneal curvature is less than or equal to 0.25 diopters. If yes, proceed to the next step. If "No", the process returns to step S4.

S10 is a display of the random line of sight superimposed on the patient's eye. The line is used by the surgeon as guidance for toric IOL alignment.

S11 is to maximize the red reflected illumination for the best toric IOL alignment. The IOL is embedded and the toric IOL alignment is performed by matching the IOL mark with the digital mark indicating the astigmatic angle.

S12 is the end of cataract surgery. All additional steps of cataract surgery typically follow IOL implantation.

When the camcorder operates in "alignment mode" during XY alignment of the microscope and removable keratometer with the patient's eye, the video camera operates in a full frame setting and covers a wide field of view. Once the alignment is done, the keratometer can be switched to a "measurement step". By switching to the camera's "window generation" mode during the measurement step, it is possible to obtain dramatically more measurements faster and thus improve overall measurement accuracy. FIG. 6 illustrates the concept of video camera window generation to increase the speed of framed ring image acquisition per second. The schematic is the patient's eye 601, the corneal margin 602, the first Purkinje reflex 603 of the platidling on the cornea, the pupil 604, and the region of interest (ROI) 605. The camcorder sensor has the ability to just record the small rectangular "window" 605 of the full video frame 606. For proper Purkinje image resolution, the ROI size should be at least 100 x 100 pixels. Modern CMOS cameras can have a resolution of 40 megapixels, ie 40,000,000 pixels at full frame. Therefore, a ROI of 100 x 100 = 10,000 pixels would constitute 10,000 / 40,000,000 = 0.00025 or 0.025% of the total frame area. The small rectangular "window" 605 is 0.02% to 60%, 0.02% to 30%, 5% to 50%, 5% to 40%, 10% to 30%, or 10% to 30% of the full video frame 606. It may be 15% to 25%. At 30%, the ROI area is one tenth of a full frame, and the speed of the camera frame per second is increased by about 10 times. The time for such "window" recording is significantly shorter than the full frame recording time. Therefore, switching to window generation mode increases the speed of ROI recording frames per second many times. It can be used to dramatically increase the number of frames within a suitable time for corneal curvature measurement during surgery, i.e. in less than 5 seconds, and measure accuracy by increasing the number of repeated measurements averaged for the final result. Raise.

FIG. 7 depicts an embodiment of a patient eye fixation detector based on the red fundus reflex. The red fundus reflex is similar to the red eye phenomenon in flash photography. The human fundus reflects light most effectively at 500 nm to 700 nm. The reflex remains strong at 750 nm but is invisible to the patient. A light source can be used at 750 nm to measure the amount of reflected light. The amount will depend on whether the visual axis of the patient's eye is aligned with the optical axis. Therefore, the amount of light can function as a fixation detector. In FIG. 7, the fixation detector 71 emits light directed at the patient's eye 74 by the beam splitters 72 and 73. Within the fixation detector, the polarized cube 75 is used to direct only p-polarized light to the patient's eye. The light source 76 including the collimating lens 77 directs a beam of substantially collimated light to the deflecting beam splitter cube 75. The specular reflection of the strong cornea will be reflected by vertical incidence and will maintain S-polarization. The fundus has a specular reflection component and a scattering component of return light. The scattered portion of the light would be equally divided into S-polarized light and P-polarized light. Therefore, the P-polarized portion of the fundus reflection will be reflected by the polarization beam splitter cube 75 to reach the detector 78 with the condenser lens 79. In order to further increase the sensitivity of the entire system, the light source 76 can be pulsating at a high frequency of 10 Hz to 1 MHz. The detector 78 would then have a lock-in amplifier frequency filter circuit to detect low level pulsation signals on a normal light background. Another method of fixation monitoring is to measure the roundness of the pupil and corneal margin via camera image processing.

FIG. 8 illustrates pulsed photoplatidling corneal curvature measurement for background subtraction. By pulsing the light source of the platidling, the video frame taken every second can be set to the mode in which the platidling is off. This allows you to draw two consecutive frames to minimize the background light effect. Just the third video, the fourth video ..., the nth video (n is the total number of frames) as long as you can draw two frames to minimize the background light effect. It is also possible to set the mode in which the imaging frame of the image is turned off. FIG. 8 shows a frame F1 in which the plaid ring is “on” and a frame F2 in which the plaid ring is “off”. Subtracting the brightness of each pixel in frame F2 from frame 1 yields the result of depicting the most useful platidling signal, ie, frame F3. This makes the system more stable with respect to external lighting. Also, dark background frames with platiding "off" can be imaged less frequently, for example, every ten frames, or every hundred frames. This will produce more frames containing useful images of platidling, yet the background frames will be refreshed frequently enough to compensate for the patient's eye movements.

FIG. 9 illustrates a Fourier analysis method applied to identify the refractive properties of the patient's eye. After identifying the coordinates of all points in the platidling image, all Y and X coordinates can be averaged _{to X 0} and Y _0. Subtract (XX ₀ ) and (YY ₀ ) to center the ellipse by the coordinate system as shown in step ST1. The Cartesian coordinate systems X and Y can be converted into polar coordinate systems ρ and φ. Reploting all points ρ and φ in the Cartesian plot gives the plot shown in step ST2. All [rho of all dots averaged to [rho _o, Subtracting [rho _o from all [rho coordinates, offset from zero is removed. In step ST2, the ellipse is converted into a sinusoidal plot. When the Fast Fourier Transform is applied to the plot, the amplitude A and the phase angle Φ can be obtained. (Ρ _o + A) and (ρ _o −A) give the semi-major axis and the semi-minor axis of the ellipse, respectively. In step ST3, the two parameters are converted into a slow corneal radius (Ks) and a steep corneal radius (Ks) using the calibration curve (set in S2 of FIG. 5). Then, the phase angle Φ gives an elliptical angle and an astigmatic angle of the patient's eye.

FIG. 10 depicts a calibration GUI. Full frame R1 is displayed to facilitate microscope alignment. Region R2 depicts a button that turns off the application. Areas R3 to R5 are for selecting a measurement mode, a calibration mode, and an inspection mode. Calibration and inspection modes are password protected. Graph R6 depicts calibration points and calibration curves. Region R7 is for selecting the sphere diameter currently being calibrated. The region R8 is for controlling the brightness of the illumination. The region R9 is for selecting the number of measurements to be averaged for each data point. The window R11 displays the region of interest including the calibration sphere.

FIG. 11 depicts a measurement GUI. The full frame R1 is displayed to facilitate microscopic alignment. Region R2 depicts a button that turns off the application. Areas R3 to R5 are for selecting a measurement mode, a calibration mode, and an inspection mode. Calibration and inspection modes are password protected. Graph R12 depicts one measured corneal curvature measurement parameter, ie, a running chart such as K, cylinder, angle, and the like. The region R13 is for displaying the corneal curvature measurement result. Region R14 is for inputting preoperative biometric parameters such as axial length, angle offset of the Anterior Angle for total angle astigmatism, and selecting the IOL type and formula for formulation. The angle offset of the anterior horn with respect to total corneal astigmatism is measured during an in-hospital examination of the patient using an instrument capable of total corneal measurement (combined anterior and posterior astigmatism). The region R9 is for selecting the number of measurements to be averaged. Region R15 is for displaying the selected IOL prescribing method. The area of interest, including the patient's eye, is displayed in window R11 and can be magnified within window R1. When the button on the GUI is pressed, the full frame is displayed in the window R1 and the area of interest is enlarged and displayed. The provided total corneal (anterior and posterior corneal) data are available, and the total corneal astigmatism angle differs from the anterior corneal astigmatism angle by the amount of delta, i.e., that amount is the angle of the alignment guidance line by delta only. It can be an input in the measurement GUI for offsetting.

FIG. 12 depicts a combination of a removable microscope-mounted keratometer and an optical coherence tomography (OCT) scanner head. The two channels can be easily combined by using spectrum-separated channels. Such OCTs typically operate in the spectral range of 780 nm to 900 nm, 1000 nm to 1100 nm, 1250 nm to 1400 nm, or 800 nm to 1400 nm, whereas the keratometer is in the NIR (700 nm to 900 nm) and visible (400 nm to 700 nm) ranges. Operate. Therefore, as shown, complete spectral separation between the keratometer imaging channel and the OCT imaging channel is possible. The beam splitter 1203 couples the OCT optical path and the keratometer optical path, i.e., the beam splitter 1203 reflects wavelengths above 900 nm and transmits NIR and visible wavelengths. The processing unit 1200 controls the OCT laser and scanner. The OCT signal is transferred to the OCT scanner through the optical fiber 1204. Results for guiding the surgeon can be displayed on an external video monitor 1205 mounted on a microscope or heads-up display 112 built into the microscope visual system 101. By adding OCT in this way, it becomes possible to measure the contribution of refraction on the posterior surface of the cornea and correct the contribution for better surgical results. Also, the placement of the implanted IOL can be controlled because effective lens position is a major factor in the outcome of cataract surgery. And finally, the axial length and the depth of the anterior chamber are measured by OCT.

It will be apparent to those skilled in the art that various modifications and modifications can be made in the invention without departing from the spirit or scope of the invention. Accordingly, the invention is intended to include the modifications and modifications of the invention as long as the modifications and modifications of the present invention are within the scope of the appended claims and their equivalents.

Claims (20)

An intraoperative measurement keratometer mounted under a surgical microscope,
Pratide ring that illuminates the patient's eyes,
With a video camera
A beam splitter that directs the Purkinje image of the platidling toward the video camera,
A fixation lamp that directs a beam to produce a red reflection effect to enhance patient eye fixation, fixation confirmation, or IOL imaging and cataract visualization.
A processor configured to perform a digital image enhancement method to outline the IOL features to identify refraction characteristics and keratometer parameters of the patient's eye and to aid in IOL alignment.
It is equipped with a digital display, which displays the keratometer parameters and surgical guidance information for the surgeon.
A keratometer configured such that the placid ring flashes at the frame per second rate of the video camera and skips flash for at least one frame for background recording and background subtraction. An intraoperative measurement keratometer mounted under a surgical microscope,
Pratide ring that illuminates the patient's eyes,
With a video camera
A beam splitter that directs the Purkinje image of the platidling toward the video camera,
A fixation lamp that directs a beam to produce a red reflection effect to enhance patient eye fixation, fixation confirmation, or IOL imaging and cataract visualization.
A processor configured to perform a digital image enhancement method to outline the IOL features to identify refraction characteristics and keratometer parameters of the patient's eye and to aid in IOL alignment.
It is equipped with a digital display, which displays the keratometer parameters and surgical guidance information for the surgeon.
0.02% to 30% of the Purkinje image is defined as a small region of interest window and is a keratometer used to extract information about the Purkinje image for high frame per second measurements and averaging. An intraoperative measurement keratometer mounted under a surgical microscope,
Pratide ring that illuminates the patient's eyes,
With a video camera
A beam splitter that directs the Purkinje image of the platidling toward the video camera,
A fixation lamp that directs a beam to produce a red reflection effect to enhance patient eye fixation, fixation confirmation, or IOL imaging and cataract visualization.
A processor configured to perform a digital image enhancement method to outline the IOL features to identify refraction characteristics and keratometer parameters of the patient's eye and to aid in IOL alignment.
It is equipped with a digital display, which displays the keratometer parameters and surgical guidance information for the surgeon.
With more fixation detectors
The fixation lamp is a substantially collimated visible or NIR light source for integral fixation pulsating at a frequency of 0.5 Hz to 1 MHz.
A keratometer that confirms that the fixation detector has followed the patient and accepts accurate fixation measurements. Further equipped with an integrated optical coherence tomography scanner,
The keratometer according to any one of claims 1 to 3, wherein the integrated optical coherence tomography scanner extracts information on the surface curvature, anterior chamber depth, and IOL placement of the posterior surface of the cornea. The keratometer according to any one of claims 1 to 3, wherein the digital display is incorporated in the keratometer as a digital overlay display. The keratometer according to claim 3 , wherein the substantially collimated visible or NIR light source produces a fundus reflex effect due to video contrast when always operating in "on" mode. The keratometer according to claim 6 , wherein the digital image enhancement method is applied to live video to outline a cataract lens and an IOL feature to facilitate IOL alignment. The keratometer according to claim 3 , wherein the different optical channels of the surgical microscope, the placid ring, the fixation lamp, the fixation detector, and the Purkinje image are spectrally separated for coaxial operation. Claims 1 to 3 where angle offsets in degrees are applied to ensure the difference between anterior corneal astigmatism and total corneal astigmatism, and the combination of anterior corneal astigmatism and posterior corneal astigmatism is applied to the GUI. keratometer according to any one. Steps to receive Purkinje and background images of the patient's eye with proper control of the placid ring and fixation lamp from a keratometer video camera mounted under a surgical microscope.
The processor provides analysis software to identify the refraction characteristics and keratometer parameters of the patient's eye based on the Purkinje and background images, and a digital image enhancement method to outline the IOL to assist in IOL alignment. The steps to perform and
A method for measuring corneal curvature, comprising: displaying a live line indicating a specific astigmatism angle of the eye on an image of the patient's eye.
A method of measuring corneal curvature in which the placid ring flashes at the frame per second rate of the video camera and skips the flash for at least one frame for background recording and background subtraction. Steps to receive Purkinje and background images of the patient's eye with proper control of the placid ring and fixation lamp from a keratometer video camera mounted under a surgical microscope.
The processor provides analysis software to identify the refraction characteristics and keratometer parameters of the patient's eye based on the Purkinje and background images, and a digital image enhancement method to outline the IOL to assist in IOL alignment. The steps to perform and
A method for measuring corneal curvature, comprising: displaying a live line indicating a specific astigmatism angle of the eye on an image of the patient's eye.
A method of measuring corneal curvature in which different optical channels are spectrally separated for coaxial operation. Steps to receive Purkinje and background images of the patient's eye with proper control of the placid ring and fixation lamp from a keratometer video camera mounted under a surgical microscope.
The processor provides analysis software to identify the refraction characteristics and keratometer parameters of the patient's eye based on the Purkinje and background images, and a digital image enhancement method to outline the IOL to assist in IOL alignment. The steps to perform and
A method for measuring corneal curvature, comprising: displaying a live line indicating a specific astigmatism angle of the eye on an image of the patient's eye.
A step of providing a substantially collimated visible or NIR light source for integrated fixation pulsating at a frequency of 0.5 Hz to 1 MHz and an fixation detector to confirm that the patient followed.
A corneal curvature measurement method that further comprises steps to accept accurate fixation measurements. Steps to use the first, second, third and fourth Purkinje images and / or an integrated optical coherence tomography scanner to extract information about the surface curvature, anterior chamber depth, and IOL placement of the posterior surface of the cornea. The method for measuring corneal curvature according to any one of claims 10 to 12, further comprising. The method for measuring corneal curvature according to any one of claims 10 to 12, further comprising the step of using a precision diameter sphere of known size for calibration. The corneal curvature measuring method according to any one of claims 10 to 12, wherein the analysis software is configured to calculate the astigmatic angle by offset to compensate for the preoperative total corneal astigmatic angle delta. Billing, further comprising the steps of providing a visible or NIR light source is substantially collimated for fixing the eye of the patient, the steps to produce a red reflection effect to help emphasize or cataract visualizing the contrast of IOL, the Item 6. The method for measuring corneal curvature according to any one of Items 10 to 12. The refraction characteristics and live lines are displayed on a tablet PC, an external display that can be mounted on the surgical microscope, or a digital display integrated with the keratometer that puts a digital overlay into the surgeon's surgical view. The method for measuring corneal curvature according to any one of claims 10 to 12. The method for measuring corneal curvature according to any one of claims 10 to 12, wherein the analysis software applies a fast Fourier transform to analyze the Purkinje image for elliptical parameter extraction. The corneal curvature measuring method according to any one of claims 10 to 12, further comprising a step of capturing 0.02% to 30% of the Purkinje image by the video camera for high frame per second measurement and averaging. Preoperative bioassay steps and
With the keratometer calibration step,
Surgical removal step of cataract lens and
Eye pretreatment steps for measuring corneal curvature during surgery,
Microscope centering step and
Microscope height adjustment step and
LED brightness adjustment step and
The steps to achieve the patient's fixation and
The corneal curvature measurement step and
Steps to display the gaze and
The method for measuring corneal curvature according to any one of claims 10 to 12, further comprising a toric IOL embedding and alignment step.

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